While hundreds of cancer epidemiologic studies have been conducted, few have, as a primary goal, focused on identification of dietary protective factors. A population-based prospective cohort study is proposed among women in Shanghai where intake levels of many hypothesized dietary protective factors are high and diverse. The primary aims of this study are: 1) to collect baseline exposure and other information through in-person interviews and to follow-up for cancer incidence 75,000 women who are aged 40-69 years at baseline and who live in 8 communities in urban Shanghai; and 2) to collect and store, for future molecular epidemiologic studies, baseline blood and urine samples from a subset of cohort members (n=20,000) and post-diagnostic blood samples (primarily for DNA extraction) from women diagnosed, during the follow-up period, with cancers of the breast (n=220), colorectum (n=170), lung (n=120), and stomach (n=130). \his proposed study whould enable the investigators, in the first 5-year funding period, to test a spectrum of etiologic hypotheses for cancers of the breast, colorectum, lung, and stomach, with emphasis on: 1) the potential protective effects of the various foods (and their major phytochemical constituents), including tea(polyphenols), soy foods (isoflavones), allium vegetables (organosulphur compounds), crucifers (isothiocyonates, dithiolthiones, indoles), dark green-leafy vegetables, and specific oriental foods, such as bok choy, Chinese cabbage, white radish, ginger root, and ginseng; 2) the association of very low fat(particularly low saturated fat) diets with colorectal and breast cancer; and 3) lifestyle factors, such as breast-feeding, induced abortion, adolescent nutritional status, obesity/central obesity, and physical activity, particularly in relation to breast cancer risk, for which studies in Shanghai will be particularly informative. Women in China differ substantially from those in the U.S. in dietary and other exposure patterns, including their high intakes of tea, soyfoods, alliums, crucifers and many other vegetables; low intake of fat, particularly saturated fat; and high prevalence of breast feeding and induced abortion. The investigators point out that given such exposure patterns, this proposed cohort study will provide unique opportunities for the examination of many important etiologic hypotheses that cannot be addressed adequately among women in the US and other Western countries. They further note that stored blood and urine samples will be valuable for future studies of biologic variables (e.g., phytoestrogens) and common genetic factors (e.g., metabolizing enzymes) and their interaction with environmental factors in the etiology of various cancers.